Various problems are involved in the purification of liquids which are polluted with oil or the like. The purification of polluted water is important for the protection of the environment, particularly of coated waters. A purification of water which has been contaminated with oil or the like is required, for instance, after an accident in which tankers are involved, and in connection with bilge-pumping and tank-flushing operations. Because suitable processes and apparatus were not available, the previous practice has been simply to pump contaminated water overboard. This has resulted in considerable water pollution.
All previously known devices for purifying liquids which are polluted with oil or the like have numerous disadvantages. The polluted liquid has been pumped through a filter in which the liquid was to be purified. Where such apparatus is used, the liquid handled in the pump was still polluted with oil or the like so that an emulsion was formed and the increased viscosity of the liquid to be handled required a higher pump power. Mechanical impurities contained in the liquid often resulted in trouble in the operation of the conventional apparatus.